Overall, 55 foodborne disease outbreaks were registered in Denmark in 2024, nine fewer than in 2023. While salmonella accounted for fewer outbreaks than in the previous year, the total number of reported salmonella cases remained at the same level. This was largely due to three major salmonella outbreaks — one linked to rocket salad and baby spinach, and two to minced beef.
Outbreak caused by rare salmonella investigated through international collaboration
In 2024, a total of 159 cases of illness caused by the rare type Salmonella Umbilo were recorded in Germany, Denmark, Austria, and seven other European countries. In Denmark, 22 people were ill. The outbreak was traced to rocket salad and baby spinach from an Italian food company.
“The Salmonella Umbilo outbreak was identified through close collaboration between partners in Denmark, Germany, and Austria, underlining the importance of international coordination in foodborne diseases. Denmark increasingly contributes to a shared EU database, managed by food and health authorities, which will become mandatory from 2026,” says senior researcher Brian Lassen at the DTU National Food Institute.
Salmonella Umbilo was first detected in rocket salad in Austria and later in baby spinach in Germany.
“It is especially laboratory methods such as whole genome sequencing, which allows DNA-level comparison of patient samples across countries, together with the detection of the bacterium in food, that have helped us solve the Salmonella Umbilo outbreak linked to rocket salad and baby spinach,” says epidemiologist Luise Müller from Statens Serum Institut (SSI).
It is a well-known problem that fruit and vegetables, particularly from abroad, may be contaminated with bacteria, viruses, or parasites — for example, from contaminated irrigation or washing water, poor hand hygiene among harvest workers, or during transport.
“Studies from DTU and the Danish Veterinary and Food Administration (DVFA) show that rinsing lettuce with cold water can remove up to 80% of bacteria. Therefore, DVFA advises consumers to wash fruit and vegetables, especially if they are to be eaten raw,” says head of section Sørine Quaade Møller of the Danish Veterinary and Food Administration.
Salmonella outbreaks linked to minced beef
During spring 2024, two large salmonella outbreaks were investigated, with 66 and 70 people falling ill, respectively. The source was found to be minced beef. In the first outbreak, cases occurred in several European countries, and the investigation showed that the source was minced beef from England. The second outbreak was linked to beef of Danish origin. In both outbreaks, several of those affected had eaten the meat raw — either by tasting it before cooking or by consuming it as steak tartare.
“In connection with the two large salmonella outbreaks in 2024, we observed a risky trend of consumers eating raw minced beef. Although EU legislation requires minced meat to be free from salmonella, contamination can occur at the slaughterhouse, where the meat may be exposed to harmful intestinal bacteria such as salmonella or E. coli. For this reason, consumers should avoid tasting raw meat. If one wishes to eat steak tartare, minced beef specifically produced for tartare should be purchased,” says Sørine Quaade Møller.
Highlights from the 2024 zoonosis report
- There were norovirus outbreaks in restaurants, linked to raw oysters, sushi, and frozen blackberries.
- The number of campylobacter outbreaks were at the same level as in previous years – and the cause is still primarily chicken meat.
- Two prolonged listeria outbreaks linked to fish products.
- Denmark has improved the preparedness following avian influenza outbreaks in cattle in the United States.
- TBE virus (tick-borne encephalitis) identified in new areas of Denmark in 2024.
- Usutu virus was detected for the first time in birds in Denmark.
- Fox tapeworm (Echinococcus multilocularis) was found in 2.7% of foxes in Denmark.
Read more
See the full report here: Annual Report on Zoonoses in Denmark 2024.
The report can also be requested by writing to: food@food.dtu.dk.
The first annual report on zoonoses was published in 1994. The report is published by the DTU National Food Institute and prepared in collaboration with the Danish Veterinary and Food Administration and Statens Serum Institut. The three organisations form the Central Outbreak Management Group (COMG), which jointly investigates foodborne disease outbreaks.
Read more about good kitchen hygiene on the Danish Veterinary and Food Administration’s website.
